| 摘要 |
PURPOSE:To air at improvement in resolution as well as a decrease of variations in bulb characteristics by putting a steel band with adjustable tightening force around the peripheral surface of a bulb's end plate, while forcibly altering the apparent curvature of a mirror with the tightening force. CONSTITUTION:A steel band 17, which is adjustable in its tightening force, is put around the peripheral surface of an end plate 5 of a bulb 10 sealing up and end plate 5 provided with a face plate 1 and a concave-spherical mirror 6 inside the bulb, via a ringlike buffer material 18 of rubber and the like, transforming the end plate 5 curved inward by dint of the tightening force of the band 17, through which the apparent curvature of the mirror 6 is designed to be forcibly altered. In addition, setting metal fixtures 19 with an L-shaped section each are set in and fixed at the plural number of spots between the buffer material 18 and the band 17, and the bulb 10 is so designed that it can be attached to an external cabinet and so on, via the fixtures 19. With this, resolution can be improved. |
